"The empire crumbled when the ruler's indiscretions came to light."
2.verbTo break into crumbs.
"We crumbled some bread into the water."
3.verbTo mix (ingredients such as flour and butter) in such a way as to form crumbs.
"Using your fingers, crumble the ingredients with the fingertips, lifting in an upward motion, until the mixture is sandy and resembles large breadcrumbs."